1. Field of the Invention
The present invention relates generally to the art of plow blades for snow removal or other applications, and more particularly to a transparent, light weight plow blade which is especially useful with small vehicles, such as four-wheel drive passenger vehicles.
2. Description of the Prior Art
Plows of many different sizes and applications are known to the art. For example, there are municipal snow plows for highway snow clearing; truck mounted plows for smaller jobs such as the clearing of parking lots; and, there are passenger vehicle mounted plows for yet smaller jobs. An example of the latter is described in U.S. Pat. No. 4,187,624 issued to the present inventor on Feb. 12, 1980 for "Snow Plow".
The plow described in the above-mentioned patent includes a plow blade, a frame which is mounted to a vehicle, such as a passenger car, and a coupling device for those two components. The coupling component includes a pair of generally horizontal cylinders to adjust the angular orientation of the blade with respect to the longitudinal axis of the vehicle and a third cylinder coupled to a bell crank assembly for elevating or lowering the blade with respect to the surface to be plowed.
While the snow plow described in my earlier patent has achieved commercial success, it suffers from certain disadvantages when it is used with certain vehicles. Such disadvantages are shared by a number of other plows, especially those competitive plows designed for use with small cars and trucks.
The disadvantages relate primarily to weight and to the operation of the plows at night. With regard to the weight problem, most prior art plows are quite heavy when combining the frame, plow blade and coupling assembly. Naturally, the heavier the plow blade, the heavier the coupling assembly and frame must be. Increased weight decreases fuel consumption for the vehicle, causes modification of the suspension characteristics of the vehicle, makes installation more difficult, etc.
With regard to the other above-mentioned drawback of existing plows, all known plow blades are solid metal, and special lighting must be employed for nighttime plowing or any other plowing application where it is necessary to be able to see the vehicle headlights and/or turn signals. With large trucks, where the headlight level is quite high, these considerations may not be a problem. However, the problem becomes very important where the plow is used with smaller passenger cars or trucks. In these applications, the plow blade's upper edge may be above the level of the headlights, even when the blade is in its lowered or operating position. Headlight obstruction almost always occurs when the blade is in its elevated or travelling position. In addition to blocking the headlights, the plow blade also blocks the parking lights and turn signal indicators of most small vehicles.
The prior art solution for the latter problems have been to provide auxiliary lighting for the vehicle, such as lighting affixed to the hood or roof. Such auxiliary lighting, of course, adds to the expense of a plow system and further increases the system weight. Moreover, the use of auxiliary lighting increases the installation time, a particularly troublesome problem if the plow is only attached to the vehicle frame for occasional use.
While the prior art has been described only by reference to snow plowing applications, the problems described also exist in other types of plowing applications, such as garden plowing and earth leveling. In fact, some plows, known as multi-purpose plows, are suitable for summer jobs as well as for snow removal. In any event, a plow blade which overcomes the aforementioned difficulties would represent a significant advance in the art.